79 research outputs found
Design and simulation of the CMS first-level muon trigger track finder
No full textThe Large Hadron Collider LHC is scheduled to start operation in the year 2005 at the CERN research center. Experiments at this collider will look for extremely rare physics events hidden in an overwhelming rate of background events. It is the task of the experiment's trigger system to reduce the total event rate to a level that can be recorded permanently for later analysis. The high reduction factor from total rate to recording rate places demands on the experiment's trigger system that go beyond any experienced at previous high-energy physics experiments. The objective of my thesis has been to design a part of that trigger system, the regional first level muon trigger, of one of the LHC experiments, the Compact Muon Solenoid (CMS) detector. At the beginning, I give a brief introduction to the LHC and its physics motivation, followed by an overview of the CMS detector. The emphasis is on the detector's muon system. Next comes a general introduction to triggering, followed by an overview of the CMS trigger system. The next part addresses the specifications of the part of the trigger I have been working on. I describe how that device is embedded into the CMS first level trigger and specify its input and output quantities. That is followed by a discussion of the requirements placed on the regional muon trigger with respect to the general trigger requirements. The environment in which the trigger has to operate is described, giving the particle rates to which the muon system is exposed and detailing the impact of the detector's magnetic field and material on the particles' trajectories. I then review several methods and techniques employed in previous and existing muon triggers. The conclusion is that none of them meets the requirements stated before. For that reason a novel algorithm had to developed. I describe that algorithm in detail and present suggestions for implementing the algorithm in hardware. That is followed by a study of the algorithm's feasibility, and I show that the algorithm is feasible and fulfills the requirements. To assess the performance of this algorithm, I created a detailed software simulation, of which a brief overview is given. Finally, I present the performance as obtained by simulation
Simulation of the silicon tracker-vertex detector of the ATLAS experiment at the Large Hadron Collider at CERN
No full textTrack finding processor in the DTBX based CMS barrel muon trigger
No full textWe present the design and simulation of the track finding processor in the DTBX ( Drift Tube with Bunch Crossing Identification) based CMS barrel muon trigger system. The processor searches for muon tracks originating from the interaction region by joining the track segments provided by the mean timer processors of the drift chambers to track strings. It assigns transverse momenta to the reconstructed tracks using the tracks' bending angle. High speed is achieved by performing the track reconstruction fully in parallel. In this contribution the algorithms, implementation and simulation results are presented
The Track Finder of the CMS First Level Muon Trigger
No full textThe track finder receives trigger primitives from drift tubes in the barrel and from cathode strip chambers in the endcap muon system. It assembles those trigger primitives to tracks, assigns transverse momentum, direction and quality to tracks and transmits these data to the global muon trigger. We present the track finder algorithm, hardware implementation and the status of the FPGA prototype
Feasibility study of the CMS first-level muon trigger track finder
No full textWe describe a feasibility study for a fast, pipelined first-level muon trigger based on measurements from drift tube chambers for the CMS experiment at LHC. The algorithm, hardware implementation and simulation results for the performance are presented. (14 refs)
Feasibility of the Hardware Muon Trigger Track Finder Processor in CMS
No full textThis paper describes a feasibility study for the design of the Muon Trigger Track Finder Processor in the high-energy physics experiment CMS (Compact Muon Solenoid, planned for 2005) at CERN. It covers the specification, proposed method, and a prototype implementation. Comparison between several other measurement methods and the proposed one are carried out. The task of the processor is to identify muons and measure their transverse momenta and locations within 350 ns. It uses data from almost two hundred thousand detector cells of drift tube muon chambers. The processor searches for muon tracks originating from the interaction point by joining the track segments provided by the drift tube muon chamber electronics to full tracks. It assigns transverse momentum to each reconstructed track using the track's bend angle
Comparison of optimization methodologies for robust feed-forward controller for gust load alleviation system
No full textThe master thesis work done by the author encompasses the design of a robust
feed-forward controller for gust load alleviation based on optimization techniques
to reduce the wing-box mass. The control methodology developed in this thesis
is independent of the aircraft platform and can be implemented any aircraft. The
author considers H2 and L00 norms in the cost function and synthesizes an optimal
feed-forward controller. The actuator limits (rate and deflection) and load factor
limits for passenger safety are included in the constraints of the optimization process.
The optimization process is carried out after determining the worst case load
scenario across the complete flight envelope and synthesizing the controller based on
that scenario so as to be robust for all fuel, mach and dynamic pressure variations.
The controller synthesized from the optimization process is transformed and reduced
to a lower order Infinite Impulse Response (IIR) filter from a higher order Finite
Impulse Response (FIR) filter. The IIR filter is further provided with a roll-off for
eliminating high frequency oscillations in the actuator. The robustness analysis is
carried out by performing Monte Carlo simulations for various parameter uncertainties.
The controller was synthesized on a linear model (longitudinal dynamics only)
with six elastic modes and it is validated on a linear model (longitudinal and lateral
dynamics) with nineteen elastic modes which includes non-linear actuators.Master of Science (Aerospace Engineering
The interaction between active aeroelastic control and structural tailoring in aeroservoelastic wing design
No full textThis paper presents an analysis of the interaction and trade-off between active aeroelastic control and passive structural tailoring on a free-flying fully flexible aircraft model. Both technologies are included in the preliminary design of a typical transport aircraft configuration with a conventional control surface layout containing trailing edge control surfaces and spoilers. The passive structural tailoring is facilitated by exploiting the anisotropic properties of composite materials to steer the static and dynamic aeroelastic behaviour. Active aeroelastic control is implemented by scheduled control surface deflections redistributing the aerodynamic loads during manoeuvres to achieve manoeuvre load alleviation and a feed-forward control law for gust load alleviation. The panel-based aerodynamic modelling of spoiler deflections is improved by a correction of the spatial distribution of the boundary condition derived from higher fidelity simulation data. The optimisation of active control laws requires the consideration of constraints of the actuation system, namely rate and deflection saturation, in a nonlinear manner. The interaction of manoeuvre load alleviation, gust load alleviation and passive structural tailoring is investigated on the basis of results of different aeroservoelastic optimisations. Therefore the primary wing structure is simultaneously optimised with the individual technologies being activated or deactivated, resulting in eight different wing structures. The results of the individual and combined optimisations reveal significant design differences. The potentials of the different technologies can only be optimally exploited by simultaneous optimisation. The paper concludes with a study of the sensitivity of the major findings with respect to the knockdown factor for failure applied to the material properties. A substantial shift of effectiveness from active aeroelastic control to passive structural tailoring is observed with increased allowables resulting in more flexible and hence less stiff wing designs.Aerospace Structures & Computational Mechanic
L-infinity-Optimal Feed-forward Gust Load Alleviatkion Design for a large Blended Wing Body Airliner
No full textL
No full textThe potential advantages of Blended Wing Body (BWB) aircraft in terms of fuel efficiency are opposed by technical challenges such as the alleviation of gust loads. Due to the low wing, loading gusts, generally, have a more severe impact on BWB aircraft than on conventional aircraft. This paper presents the design and optimization of a Gust Load Alleviation System (GLAS) for a large BWB airliner. Numerical simulations are performed with an aeroelastic model of the aircraft including GLAS in order to compute time series of modal displacements for deriving equivalent static load cases which are used for the resizing of the aircraft structure
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